KR101775965B1

KR101775965B1 - Method and appratus for controlling air fuel ratio in dual injection engine system

Info

Publication number: KR101775965B1
Application number: KR1020150172499A
Authority: KR
Inventors: 김동하; 김진성
Original assignee: 현대오트론 주식회사
Priority date: 2015-12-04
Filing date: 2015-12-04
Publication date: 2017-09-07
Also published as: KR20170066011A

Abstract

The present invention relates to a method and an apparatus for controlling the air-fuel ratio of a dual injection engine, and more particularly, to an air-fuel ratio control apparatus for a dual injection engine, A throttle valve for regulating the air supplied to the engine cylinder; An oxygen sensor for measuring an oxygen content contained in the exhaust gas; A GDI (Gasoline Direct Injection) fuel injector for injecting fuel in the GDI mode; A PFI (Port Fuel Injection) fuel injector for injecting fuel in the PFI mode; And a basic fuel amount for realizing a target air-fuel ratio to the engine air amount measured through the intake air pressure sensor, calculates a current air-fuel ratio based on the oxygen content measured through the oxygen sensor, compares the current air- Fuel ratio correction is necessary, and determines the air-fuel ratio learning condition by referring to the engine torque and the engine speed when the fuel amount correction is necessary. If it is determined that the air-fuel ratio learning condition is the first learning condition, the GDI fuel Calculating a plurality of multiplication learning values corresponding to the injection ratios of the GDI fuel injector and the PFI fuel injector when the second learning condition is satisfied as a result of the determination, calculating a fuel amount to be added to or subtracted from the injector or the PFI fuel injector, And corrects the fuel injection amount through the calculated learning value It includes an engine controller for controlling the fuel injector or the group GDI PFI fuel injectors.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and an apparatus for controlling the air-fuel ratio of a dual injection engine,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control method and apparatus, and more particularly, to an engine control method and apparatus by learning an air-fuel ratio of a dual injection engine.

The autocycle and the diesel cycle are mainly used in the automobile engine, the autocycle is mainly used for the petrol vehicle, and the diesel cycle is used for the diesel vehicle.

Especially, the auto-cycle internal combustion engine has been used in various fields for a long time, and technological progress has been made especially as a main power source of the vehicle.

The autocycle engine is classified into a port fuel injection (PFI) method and a direct injection (GDI) method according to the injection method.

The port injection (PFI) method injects fuel into the intake manifold by injecting the injector into the intake manifold, and sucks the fuel in the intake stroke as it is burned.

The direct injection (GDI) method injects the injector directly into the combustion chamber like a diesel engine, which reduces fuel consumption compared to port injection, and is capable of producing high output and reducing exhaust gas.

On the other hand, the direct injection (GDI) method has advantages of improving the power performance and improving the fuel efficiency, and gradually, the direct injection type engine is widely used instead of the existing port injection type engine. However, the GDI method has disadvantages that air pollution and human body are adversely affected because a part of the injected fuel is generated as particulate matter. As a result, major developed countries are adopting policies to curb PM (Particulate Mass) and PN (Particulate Number) emissions through legal regulations, and vehicle makers are seeking various solutions to reduce particulate emissions.

One alternative is the dual injection engine (PDI: PFI and GDI), which combines direct injection and port injection. The dual injection engine is configured to add a port injection injector to the existing direct injection engine, so that the desired injection ratio can be selected and used in a specific operation area. For example, the port injection method is used in a low load region where particulate matter is discharged frequently, the direct injection method is used in a high load region where performance is important, and both injection methods can be used in a region where fuel consumption reduction is required.

The present invention provides a dual injection engine control method and apparatus capable of learning an air-fuel ratio suited to each injection situation in a dual injection engine (PDI: PFI and GDI) combining direct injection and port injection systems .

It is another object of the present invention to provide a dual injection engine control method and apparatus capable of correcting an air-fuel ratio deviation more accurately than an existing single learning value method by recognizing a system deviation.

A method for controlling an air-fuel ratio of a dual injection engine according to an embodiment of the present invention is a method for controlling an air-fuel ratio of a dual injection engine including a GDI (Gasoline Direct Injection) fuel injector and a PFI (Port Fuel Injection) fuel injector, ; Calculating a base fuel amount for realizing a target air-fuel ratio to the measured engine air amount; Calculating the current air-fuel ratio by injecting the calculated base fuel amount; Comparing the current air-fuel ratio with a target air-fuel ratio to determine whether fuel amount correction is necessary; Determining the air-fuel ratio learning condition by referring to the engine torque and the engine speed when the fuel amount needs to be corrected as a result of the determination; If it is determined that the first learning condition is satisfied, the amount of fuel to be added to or subtracted from the GDI fuel injector or the PFI fuel injector involved in the present fuel injection is calculated as a learning value, Calculating a plurality of multiplication learning values according to an injection ratio of the GDI fuel injector and the PFI fuel injector; And correcting the fuel injection amount based on the calculated learning value.

The air-fuel ratio learning condition determination step may include at least one of a coolant temperature, an intake temperature, an air-fuel ratio feedback control operation, a canister purge valve operation, an intake pressure sensor abnormality, a fuel injector abnormality, Fuel ratio learning condition is determined by referring to the air-fuel ratio learning condition.

The first learning condition is characterized by a low load or an idle state in which the current engine speed and the engine torque are low.

The second learning condition is characterized by a middle / high load state in which the current engine speed and the engine torque are high.

Preferably, the engine speed is 1500 rpm or more, and the engine torque is in a range of 25% or more and 60% or less.

If the first learning condition is satisfied, it is determined whether or not the mode is the single injection mode. If the mode is the single injection mode, it is determined whether the mode is the GDI single injection mode. If the mode is the GDI single injection mode, , The PFI mode addition factor is learned when the mode is not the GDI single injection mode, and the learning value is reflected in the fuel amount calculation.

When the second learning condition is satisfied, a predetermined multiplication factor having a sum of the GDI injection ratio and the PFI injection ratio of 100% is learned, and the learning value according to the injection ratio is stored in the memory cell .

An air-fuel ratio control apparatus for a dual injection engine according to an embodiment of the present invention includes an intake air pressure sensor for measuring an engine air amount; A throttle valve for regulating the air supplied to the engine cylinder; An oxygen sensor for measuring an oxygen content contained in the exhaust gas; A GDI (Gasoline Direct Injection) fuel injector for injecting fuel in the GDI mode; A PFI (Port Fuel Injection) fuel injector for injecting fuel in the PFI mode; And a basic fuel amount for realizing a target air-fuel ratio to the engine air amount measured through the intake air pressure sensor, calculates a current air-fuel ratio based on the oxygen content measured through the oxygen sensor, compares the current air- Fuel ratio correction is necessary, and determines the air-fuel ratio learning condition by referring to the engine torque and the engine speed when the fuel amount correction is necessary. If it is determined that the air-fuel ratio learning condition is the first learning condition, the GDI fuel Calculating a plurality of multiplication learning values corresponding to the injection ratios of the GDI fuel injector and the PFI fuel injector when the second learning condition is satisfied as a result of the determination, calculating a fuel amount to be added to or subtracted from the injector or the PFI fuel injector, And corrects the fuel injection amount through the calculated learning value It includes an engine controller for controlling the fuel injector or the group GDI PFI fuel injectors.

In addition, the apparatus further includes a memory cell in which a plurality of multiplication learning values corresponding to the injection ratios of the GDI fuel injector and the PFI fuel injector are recorded and stored.

The first learning condition is a low load or an idle state in which the current engine speed and engine torque are low and the second learning condition is a middle or high load state in which the current engine speed and engine torque are high. do.

According to an embodiment of the present invention, there is an effect of providing a dual injection engine control method and apparatus capable of learning an air-fuel ratio suited to each injection situation in a dual injection engine (PDI; PFI and GDI) combining direct injection and port injection.

Further, there is an effect of providing a dual injection engine control method and apparatus capable of correcting an air-fuel ratio deviation more accurately than an existing single learning value method by recognizing a system deviation.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of a dual injection engine control apparatus according to one embodiment of the present disclosure;
2 is a reference diagram for explaining the air-fuel ratio learning region of the present specification.
3 is a view showing the reflection of the air / fuel ratio learning fuel amount according to the embodiment of the present invention.
4 is a flowchart sequentially illustrating addition factor learning according to an embodiment of the present invention;
FIG. 5 is a flowchart sequentially showing multiplication factor learning according to an embodiment of the present invention; FIG.
6 is a reference diagram for illustrating storing a multiplication factor in a memory cell according to an embodiment of the present disclosure;

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In describing the embodiments, descriptions of techniques which are well known in the technical field to which this specification belongs and which are not directly related to this specification are not described. This is for the sake of clarity without omitting the unnecessary explanation and without giving the gist of the present invention.

For the same reason, some of the components in the drawings are exaggerated, omitted, or schematically illustrated. Also, the size of each component does not entirely reflect the actual size. In the drawings, the same or corresponding components are denoted by the same reference numerals.

1 is a schematic view of a dual injection engine control apparatus according to an embodiment of the present invention.

As shown, the dual injection engine control device includes an intake pressure sensor 10, a throttle valve 20, an oxygen sensor 30, a GDI fuel injector 40, a PFI fuel injector 50, an engine 60, And a controller (100).

The amount of air flowing into the engine is measured through the intake air pressure sensor 10, and a flow rate sensor may be used.

The throttle valve 20 is a valve that opens and closes to regulate the amount of air passing through the throttle body. The engine controller 100 adjusts the degree of opening of the valve depending on the degree of depression of the accelerator pedal. Generally, when the air passes through the throttle valve 20 a large amount of fuel must be injected.

The oxygen sensor 30 measures the oxygen content contained in the exhaust gas.

Therefore, the engine controller 100 calculates the basic fuel amount by multiplying the air flow rate measured through the intake air pressure sensor 10 or the flow rate sensor by a certain ratio in order to realize the target air-fuel ratio. Then, when the calculated basic fuel amount is injected and combustion occurs, the present air-fuel ratio is grasped through the oxygen sensor 30. Then, the difference between the detected current air-fuel ratio and the target air-fuel ratio can be calculated and the fuel-acceleration / exhaust amount for maintaining the target air-fuel ratio can be calculated.

On the other hand, in the case of an autocycle engine, exhaust gas composed of major components such as HC, CO, and NOx is generated, which is subject to legal regulations due to air pollution and human influence. Currently, most vehicles use a three way catalyst that can reduce major emission factors through oxidation and reduction reactions. The three-way catalyst has the maximum conversion efficiency when the air-to-fuel ratio (air-fuel ratio) of the exhaust gas is maintained in the stoichiometric air-fuel ratio region, and maintaining the stoichiometric air-fuel ratio under various operating conditions is a core technology of exhaust gas reduction. Currently, most vehicles use a feedback control method based on the oxygen sensor 30 signal for the control of the stoichiometric air-fuel ratio. This method is based on the combustion of the fuel injected at the fuel injection amount calculated by the engine controller 100 based on the measured intake air amount And calculates the actual air-fuel ratio through the oxygen sensor 30 signal attached to the rear exhaust. At this time, if the air-fuel ratio deviates from the stoichiometric air-fuel ratio, the engine controller 100 for controlling the air-fuel ratio calculates the necessary fuel addition / reduction amount and reflects it continuously in the fuel injection amount calculation.

In general, most of the components involved in the combustion of the engine all have tolerances, which cause various air-fuel ratio errors for each vehicle. From the viewpoint of fuel injection quantity, there are two main types. That is, it is a multiplication factor caused by factors such as fuel component and fuel pressure, and a plus factor due to injector injection delay and the like. The double addition factor can be measured in an area with a small fuel injection amount (for example, an idle area), and the multiplication factor can be measured in a middle / high load area requiring a constant injection amount. Since this error causes a constant air-fuel ratio deviation, the air-fuel ratio controller in the engine controller includes a function of learning and automatically compensating for this error.

However, in the case of the single injection type engine, one learning value can be calculated and stored for each error. However, in the case of the dual injection type such as the PDI engine, the existing single learning value has the error value Is not properly reflected. Accordingly, the present invention proposes a method of calculating different learning values for each injection method and reflecting the learned values on the fuel injection amount.

That is, the engine controller 100 calculates the base fuel amount for realizing the target air-fuel ratio to the engine air amount measured through the intake air pressure sensor 10, and calculates the current air-fuel ratio based on the oxygen content measured through the oxygen sensor 30 . Then, the current air / fuel ratio is compared with the target air / fuel ratio to determine whether the fuel amount correction is necessary. When the fuel amount correction is necessary, the air / fuel ratio learning condition is determined with reference to the engine torque and the engine speed.

Fuel ratio to be added to or subtracted from the GDI fuel injector 40 or the PFI fuel injector 50 involved in the present fuel injection in the case of an additive learning condition, Are calculated as addition learning values, respectively.

The addition learning value is mainly calculated for controlling the stoichiometric air-fuel ratio in the idle region. If the difference in fuel injection amount based on the air amount measured in the idle region continuously occurs, it is necessary to change the opening timing of the fuel injector. This should be calculated as the amount of opening that must be added or reduced regardless of the amount of basic opening before the calculation of the feedback control value. In the case of a dual injection engine, the amount of opening to be added or subtracted to the fuel injector involved in the current injection must be calculated separately, and then added to the fuel injection amount calculation of the individual fuel injector.

When the multiplication learning condition is satisfied as a result of the air-fuel ratio learning condition determination, a plurality of multiplication learning values corresponding to the injection ratios of the GDI fuel injector 40 and the PFI fuel injector 50 are calculated.

The multiplication learning value is calculated for controlling the stoichiometric air-fuel ratio in almost all the operation regions except for the idle region. The difference between the fuel injection quantities other than the idle region occurs with a deviation corresponding to a certain ratio of the basic opening amount, and the engine controller calculates a certain ratio as the air-fuel ratio learning value and reflects the fuel injection amount. In the case of a single fuel injection engine, the deviation can be corrected by only one learned value. However, in the case of a plurality of factors causing the air-fuel ratio deviation, such as a dual injection engine, There is a problem that it can not be corrected. Therefore, in the case of the dual injection engine, it is possible to obtain accurate control results by calculating and storing a plurality of multiplication learning values according to the injection ratio and correcting the learning values corresponding to the current injection mode.

Thereafter, the GDI fuel injector 40 or the PFI fuel injector 50 is controlled by correcting the fuel injection amount through the learning value calculated as described above.

2 is a reference diagram for explaining the air-fuel ratio learning region of the present specification.

First, the common air-fuel ratio learning conditions common to both the addition and multiplication factors are that the cooling water temperature is higher than a certain temperature (for example, 60 degrees), the intake temperature is lower than a predetermined temperature (for example, 80 degrees) It can be judged by checking whether the purge valve is not operated or the related parts (intake pressure sensor, fuel injector, oxygen sensor, etc.) are abnormal.

The canister is a functional means of storing the gasoline gas produced in the fuel tank. The collected gasoline gas is sent to the engine at the appropriate time when the engine is operating, and burned in the engine. This is referred to as evaporative gas control or canister purge control.

As shown in the figure, the addition learning condition corresponds to a low load region in which the engine torque satisfies the range of 5% to 10% and the engine rotational speed satisfies 600 rpm to 1000 rpm.

Also, the multiplication learning condition corresponds to a medium load range in which the engine torque satisfies the range of 25% to 60% and the number of engine revolutions satisfies 1500 rpm to 3000 rpm.

The air-fuel ratio learning method suitable for each injection situation is applied to the dual injection engine control device of the present invention, and the air-fuel ratio learning and correction are performed so as to match the low load / idle region and the medium load region characteristics.

FIG. 3 is a diagram showing the reflection of the air / fuel ratio learning fuel amount according to the embodiment of the present invention.

First, based on the intake air pressure or the intake air flow sensor value, a correction value for a factor affecting the experiment is obtained, and the correct air amount of the current engine is measured after the correction.

Then, a plus factor is calculated and added during learning of the air-fuel ratio. The addition learning is to control the injection pulse width (i.e., injection pulse time open) for the entire engine operating region. The addition learning is mainly performed in the idle or low load engine operating region, and the amount of fuel change is very small because a relatively small amount of air is introduced. For example, the engine controller ECU monitors the oxygen sensor and adjusts the injection pulse time by approximately 0.001 msec to maintain the stoichiometric air-fuel ratio (Lambda = 1). Such an increase or decrease in the injection pulse width is referred to as an additive adaptation value.

Then, the fuel amount is controlled to the target air-fuel ratio at the stoichiometric air-fuel ratio based on the measured air amount. For example, in the case of a gasoline engine, the stoichiometric air-fuel ratio at which the exhaust gas purifying efficiency of the three-way catalyst is maximized is 14.7: 1 at the air-to-fuel ratio, so that the basic fuel injection amount can be 14.7 divided by the measured air amount.

Then, the air-fuel ratio of the present exhaust gas is measured through the oxygen sensor signal. At this time, feedback control is performed to adjust the oxygen sensor signal to the air-fuel ratio of 14.7 in order to correct the deviation of the air-fuel ratio caused by the system deviation (air amount measurement error, related part tolerance, etc.). For example, when the oxygen sensor signal is measured as a lean air-fuel ratio (16: 1), the oxygen sensor signal is multiplied by a constant coefficient (1.08 = 16 / 14.7) (0.84 = 12.3 / 14.7) so as to reduce the base fuel amount. In the present invention, the constant coefficient corresponds to the output value of the air-fuel ratio controller of FIG.

Then, a multiplicative adaptation value is calculated and multiplied during learning of the air-fuel ratio. The multiplication factor is measured as a '%' value. The dual injection engine can adjust the injection ratio between GDI and PFI according to the driving area as required. Generally, the low load area uses PFI for PN emission reduction purpose and GDI injection The rate increases. Since the fuel amount for keeping the stoichiometric air-fuel ratio with respect to the engine intake air amount is fixed, the sum of the injection ratios of PFI / GDI should always be 100%, and the fuel amount to be injected by each individual fuel injector can be determined by adjusting the injection ratio have. For example, if the PFI is 20%, the GDI can be injected at 80%. Further, if the PFI is 40%, the GDI can be injected at 60%.

When the above values are reflected, the fuel amount may be determined for each injection mode.

4 is a flowchart sequentially illustrating addition factor learning according to an embodiment of the present invention.

In step S10, the engine controller 100 determines whether the learning condition is satisfied based on the engine torque and the engine speed.

If it is in the idle or low load operation region, it is determined as a plus learning condition, and it is determined whether the mode is the single injection mode (S11).

In the case of the single injection mode, it is determined whether the mode is the GDI single injection mode (S12), the GDI mode addition factor is learned in the case of the GDI single injection mode (S13), and the PFI mode addition factor (S14).

Then, the addition learning value for each mode is reflected to the fuel amount calculation (S15).

5 is a flowchart sequentially illustrating multiplication factor learning according to an embodiment of the present invention.

The engine controller 100 determines whether the learning condition is multiplied based on the engine torque and the engine speed (S20).

If it is in the high-load operation region, it is determined as a multiplication learning condition, and a multiplication factor is learned (S21). At this time, the multiplication factor is calculated by the GDI injection ratio and the PFI injection ratio, and the sum of them is 100%.

The learning value according to the currently calculated injection ratio is stored in the corresponding memory cell (S22).

Then, the multiplication factor is reflected in the fuel amount calculation (S23).

6 is a reference diagram for illustrating storing a multiplication factor in a memory cell according to an embodiment of the present invention.

As shown in the figure, in the case of the multiplication learning value, the learning values are stored in different cell (memory) regions according to the current injection mode when entering the learning region. For example, in the case of using 10 cells for storing the multiplication learning value, N in FIG. 5 is set to 10. Therefore, the total number of memory areas in FIG. 5 is 10, and the multiplication learning value in the first cell is stored in the fuel injection quantity when the GDI is 0 to 10% (PFI 100 to 90%) injection mode. In the second cell, the multiplication learning value in the case of the GDI 10% to 20% (PFI 90% to 80%) injection mode is stored and used for the fuel amount calculation. In this manner, the respective injection mode multiplication learning values from the third cell to the tenth cell can be stored and used for fuel amount calculation.

The size of the multiplication factor storage cell can be adjusted according to the operation method of the corresponding system. For example, in a system using only five injection modes in a non-continuous manner, five cells are used and a continuous injection mode is used In the case of the system, the size of the cell can be specified within the memory usable range of the controller.

It will be understood by those skilled in the art that the present specification may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present specification is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present specification Should be interpreted.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It is not intended to limit the scope of the specification. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

10: Intake pressure sensor 20: Throttle valve
30: Oxygen sensor 40: GDI fuel injector
50: PFI fuel injector 60: engine
100: engine controller

Claims

A method for controlling an air-fuel ratio of a dual injection engine including a GDI (Gasoline Direct Injection) fuel injector and a PFI (Port Fuel Injection) fuel injector,
Measuring an engine air amount;
Calculating a base fuel amount for realizing a target air-fuel ratio to the measured engine air amount;
Calculating the current air-fuel ratio by injecting the calculated base fuel amount;
Comparing the current air-fuel ratio with a target air-fuel ratio to determine whether fuel amount correction is necessary;
Determining the air-fuel ratio learning condition by referring to the engine torque and the engine speed when the fuel amount needs to be corrected as a result of the determination;
If it is determined that the first learning condition is satisfied, the amount of fuel to be added to or subtracted from the GDI fuel injector or the PFI fuel injector involved in the present fuel injection is calculated as a learning value, Calculating a plurality of multiplication learning values according to an injection ratio of the GDI fuel injector and the PFI fuel injector; And
And correcting the fuel injection amount based on the calculated learning value.

2. The method according to claim 1,
It is determined whether or not the air-fuel ratio learning condition is satisfied by referring to at least one of the temperature of the cooling water, the intake air temperature, whether or not the air-fuel ratio feedback control operation is performed, whether the canister purge valve operates, the intake air pressure sensor abnormality, the fuel injector abnormality, Fuel ratio of the internal combustion engine.

2. The learning method according to claim 1,
Wherein the current engine speed and the engine torque are in a low load or an idle state lower than the reference value.

2. The method according to claim 1,
Wherein the current engine speed and the engine torque are in a middle / high load state higher than a reference value.

5. The method of claim 4,
Wherein the engine speed is at least 1500 rpm and the engine torque is at least 25% and at most 60%.

2. The method according to claim 1, wherein, when the first learning condition is satisfied,
It is determined whether or not the mode is the single injection mode. In the case of the single injection mode,
GDI single injection mode,
GDI mode addition factor in GDI single injection mode, learning PFI mode addition factor when not GDI single injection mode,
And the learning value is reflected in the fuel amount calculation.

2. The method according to claim 1, wherein, when the second learning condition is satisfied,
The predetermined multiplication factor with the sum of the GDI injection ratio and the PFI injection ratio being 100% is learned,
Wherein the learning value according to the injection ratio is stored in the memory cell.

An intake air pressure sensor for measuring an engine air amount;
A throttle valve for regulating the air supplied to the engine cylinder;
An oxygen sensor for measuring an oxygen content contained in the exhaust gas;
A GDI (Gasoline Direct Injection) fuel injector for injecting fuel in the GDI mode;
A PFI (Port Fuel Injection) fuel injector for injecting fuel in the PFI mode; And
A basic fuel quantity for realizing a target air-fuel ratio is calculated for the engine air quantity measured through the intake air pressure sensor, a current air-fuel ratio is calculated based on the oxygen content measured through the oxygen sensor, Fuel ratio correction is required, and determines the air-fuel ratio learning condition by referring to the engine torque and the engine speed when the fuel amount correction is required. If the air-fuel ratio learning condition is determined to be the first learning condition, the GDI fuel injector Or the PFI fuel injector is calculated as the addition learning value, and if the second learning condition is satisfied, a multiplication learning value corresponding to the injection ratio of the GDI fuel injector and the PFI fuel injector is calculated , The fuel injection amount is corrected through the calculated learning value GDI fuel injector or engine controller for controlling the PFI fuel injectors;
Fuel ratio control system for a dual injection engine.

9. The method of claim 8,
Further comprising a memory cell in which a plurality of multiplication learning values corresponding to the injection ratios of the GDI fuel injector and the PFI fuel injector are recorded and stored.

9. The method of claim 8,
The first learning condition is a low load or idle state in which the current engine speed and the engine torque are lower than the reference value,
Wherein the second learning condition is a middle / high load state in which the current engine speed and the engine torque are higher than the reference value.